The present invention generally relates to couplings for use with load-lifting devices and safety restraints such as cables, chains, and ropes and, more particularly, is concerned with a lockable, pin-retaining coupling which remains securely locked until released, and once released is held in the released position without regard to its orientation to the vertical, and in which the component parts are not subject to disassembly and subsequent loss.
The ability to transfer a load from a lifting device such as a hoist or derrick or crane without concern for the loss of component parts of the coupling device is important in industrial settings such as factories and quarries, and in construction.
Similarly, individuals requiring tethers to safety equipment while engaged in hazardous sports or occupations such as mountain climbing or window washing require a coupling which is easily and quickly operable, without fear of losing parts, without fear of either uncoupling during use or closing and becoming coupled before being attached to the necessary equipment.
Present couplings in use take the form of elongated links which close either by latching upon pins or close by means of a threaded nut, and are subject to being distorted or sprung out of shape while in use, thus making the locking or securing portions of these couplings inoperable. The couplings become unsafe under these circumstances.
Other couplings are held together by threaded nuts which require the use of wrenches and which often vibrate loose while in use.
In one general type of coupling the pin is simply held in position by a cotter pin or clamp which often becomes lost in usage. In another general type, pin locking means have been complex and uneconomical to manufacture or otherwise are overly bulkly and undesirable in use.
U.S. Pat. No. 4,068,960 discloses a clevis and pin style coupling which remains latched in the closed position.
It is therefore highly desirable to provide an improved coupling and an improved locking means for a load bearing pin.
It is also highly desirable to provide an improved coupling having a pin, a clevis and a retractable latch to hold the pin in position.
It is also highly desirable to provide an improved coupling having a pin, clevis and a brake restraining the movement of the pin within the clevis when the pin is in other than a fully engaged position.
It is also highly desirable to provide an improved coupling having a clevis and a pin with stops which prevent the pin from being removed from the clevis.
It is also highly desirable to provide a relatively simple, economical and safe locking means for a load bearing pin.
It is also highly desirable to provide an improved coupling having a clevis and a pin with both a latch to prevent inadvertent opening of the coupling and a brake to prevent inadvertent movement of the pin within the clevis.
It is also desirable to provide an improved coupling with these features by economical, maintenance free and readily available mechanical means with a minimum of mechanical parts and with a minimum of fabrication required on the parts in a mechanically simple structure which is convenient to use.
It is also highly desirable to provide an improved coupling which may be coupled and uncoupled by untrained users, conveniently, without the use of tools.
It is also highly desirable to provide a coupling which when open will remain open despite its orientation and will not be closed prematurely due to the force of gravity.
It is also highly desirable to provide an improved coupling and load bearing pin assembly which has all of the above-identified features.